#region Copyright & License Information
/*
* Copyright 2007-2013 The OpenRA Developers (see AUTHORS)
* This file is part of OpenRA, which is free software. It is made
* available to you under the terms of the GNU General Public License
* as published by the Free Software Foundation. For more information,
* see COPYING.
*/
#endregion

using System.Text;
using SDL2;

namespace OpenRA.Renderer.Sdl2
{
	public class Sdl2Input
	{
		MouseButton lastButtonBits = (MouseButton)0;

		static MouseButton MakeButton(byte b)
		{
			return b == SDL.SDL_BUTTON_LEFT ? MouseButton.Left
				: b == SDL.SDL_BUTTON_RIGHT ? MouseButton.Right
				: b == SDL.SDL_BUTTON_MIDDLE ? MouseButton.Middle
				: 0;
		}

		static Modifiers MakeModifiers(int raw)
		{
			return ((raw & (int)SDL.SDL_Keymod.KMOD_ALT) != 0 ? Modifiers.Alt : 0)
				 | ((raw & (int)SDL.SDL_Keymod.KMOD_CTRL) != 0 ? Modifiers.Ctrl : 0)
				 | ((raw & (int)SDL.SDL_Keymod.KMOD_LGUI) != 0 ? Modifiers.Meta : 0)
				 | ((raw & (int)SDL.SDL_Keymod.KMOD_RGUI) != 0 ? Modifiers.Meta : 0)
				 | ((raw & (int)SDL.SDL_Keymod.KMOD_SHIFT) != 0 ? Modifiers.Shift : 0);
		}

		public void PumpInput(IInputHandler inputHandler)
		{
			var mods = MakeModifiers((int)SDL.SDL_GetModState());
			var scrollDelta = 0;
			inputHandler.ModifierKeys(mods);
			MouseInput? pendingMotion = null;

			SDL.SDL_Event e;
			while (SDL.SDL_PollEvent(out e) != 0)
			{
				switch (e.type)
				{
					case SDL.SDL_EventType.SDL_QUIT:
						Game.Exit();
						break;

					case SDL.SDL_EventType.SDL_WINDOWEVENT:
					{
						switch (e.window.windowEvent)
						{
							case SDL.SDL_WindowEventID.SDL_WINDOWEVENT_FOCUS_LOST:
								Game.HasInputFocus = false;
								break;

							case SDL.SDL_WindowEventID.SDL_WINDOWEVENT_FOCUS_GAINED:
								Game.HasInputFocus = true;
								break;
						}

						break;
					}

					case SDL.SDL_EventType.SDL_MOUSEBUTTONDOWN:
					{
						if (pendingMotion != null)
						{
							inputHandler.OnMouseInput(pendingMotion.Value);
							pendingMotion = null;
						}

						var button = MakeButton(e.button.button);
						lastButtonBits |= button;

						var pos = new int2(e.button.x, e.button.y);

						inputHandler.OnMouseInput(new MouseInput(
							MouseInputEvent.Down, button, scrollDelta, pos, mods,
							MultiTapDetection.DetectFromMouse(e.button.button, pos)));

						break;
					}

					case SDL.SDL_EventType.SDL_MOUSEBUTTONUP:
					{
						if (pendingMotion != null)
						{
							inputHandler.OnMouseInput(pendingMotion.Value);
							pendingMotion = null;
						}

						var button = MakeButton(e.button.button);
						lastButtonBits &= ~button;

						var pos = new int2(e.button.x, e.button.y);
						inputHandler.OnMouseInput(new MouseInput(
							MouseInputEvent.Up, button, scrollDelta, pos, mods,
							MultiTapDetection.InfoFromMouse(e.button.button)));

						break;
					}

					case SDL.SDL_EventType.SDL_MOUSEMOTION:
					{
						pendingMotion = new MouseInput(
							MouseInputEvent.Move, lastButtonBits, scrollDelta,
							new int2(e.motion.x, e.motion.y), mods, 0);

						break;
					}

					case SDL.SDL_EventType.SDL_MOUSEWHEEL:
					{
						int x, y;
						SDL.SDL_GetMouseState(out x, out y);
						scrollDelta = e.wheel.y;
						inputHandler.OnMouseInput(new MouseInput(MouseInputEvent.Scroll, MouseButton.None, scrollDelta, new int2(x, y), Modifiers.None, 0));

						break;
					}

					case SDL.SDL_EventType.SDL_TEXTINPUT:
					{
						string input;
						unsafe
						{
							var data = new byte[SDL.SDL_TEXTINPUTEVENT_TEXT_SIZE];
							var i = 0;
							for (; i < SDL.SDL_TEXTINPUTEVENT_TEXT_SIZE; i++)
							{
								var b = e.text.text[i];
								if (b == '\0')
									break;

								data[i] = b;
							}

							input = Encoding.UTF8.GetString(data, 0, i);
						}

						inputHandler.OnTextInput(input);
						break;
					}

					case SDL.SDL_EventType.SDL_KEYDOWN:
					case SDL.SDL_EventType.SDL_KEYUP:
					{
						var keyCode = (Keycode)e.key.keysym.sym;
						var type = e.type == SDL.SDL_EventType.SDL_KEYDOWN ?
							KeyInputEvent.Down : KeyInputEvent.Up;

						var tapCount = e.type == SDL.SDL_EventType.SDL_KEYDOWN ?
							MultiTapDetection.DetectFromKeyboard(keyCode) :
							MultiTapDetection.InfoFromKeyboard(keyCode);

						var keyEvent = new KeyInput
						{
							Event = type,
							Key = keyCode,
							Modifiers = mods,
							UnicodeChar = (char)e.key.keysym.sym,
							MultiTapCount = tapCount
						};

						// Special case workaround for windows users
						if (e.key.keysym.sym == SDL.SDL_Keycode.SDLK_F4 && mods.HasModifier(Modifiers.Alt) &&
							Platform.CurrentPlatform == PlatformType.Windows)
							Game.Exit();
						else
							inputHandler.OnKeyInput(keyEvent);

						break;
					}
				}
			}

			if (pendingMotion != null)
			{
				inputHandler.OnMouseInput(pendingMotion.Value);
				pendingMotion = null;
			}

			ErrorHandler.CheckGlError();
		}
	}
}